CARBON NANOTUBES-GRAPHITE PASTE ELECTRODE MODIFIED WITH Cu(II)-EXCHANGED ZEOLITE FOR H2O2 DETECTION

Modification of a natural zeolite from Macicas (Cluj County, Romania) with copper(II) (Z-Cu), followed by its incorporation in carbon paste, made of carbon nanotubes and graphite powder as conductive matrix (Z-Cu-G-CNT- CPEs), lead to a stable modified electrode. The Z-Cu-G-CNT-CPEs electrodes show significant electrocatalytic activity toward H2O2 reduction. The rate constant for catalytic H2O2 reduction, estimated from rotating disk electrode measurements, extrapolated to zero H2O2 concentration was found to be 74.4 M-1 s(-1) (pH 7). The amperometric detection of H2O2, at -400 mV vs. Ag/AgCl/KClsat is characterized by the following electroanalytical parameters: sensitivity of 15.33 mA M-1, detection limit of 0.24 mM and linear domain up to 10 mM H2O2.